1795 To 1961
Many residents of colonial Santo Domingo, now the Dominican Republic, left for Puerto Rico as a consequence of the cession of Santo Domingo to France in 1795, the Haitian invasions from 1801-1803 and later occupation from 1822-1844. Immigration continued over the next 86 years, although at a comparatively low rate.
The dictatorship of Rafael Trujillo between 1930 and 1961, greatly constrained foreign travel by Dominicans. In 1960 there were 1,812 Dominicans in Puerto Rico, some of whom were the 'returning' descendants of Puerto Ricans who had themselves migrated to the Dominican Republic.
Read more about this topic: Dominican Immigration To Puerto Rico